Flight Testing Failures Create Learning Curve

The hypersonics community is accustomed to failure, but that has done nothing to temper the deep disappointment after the X-51A Waverider demonstrator's third flight ended before its supersonic-combustion ramjet engine could be fired. The Aug. 14 test fizzled seconds after it began due to a control fin malfunction. It followed a largely successful first test in May 2010, and is the latest in a string of failures. But there have also been successes, and it is those that continue to keep the hopes for hypersonics alive. The first U.S. Air Force X-51A achieved 143 sec of scramjet-powered flight—11 times the duration set by NASA's X-43A in 2004. The rocket-boosted Army Hypersonic Weapon flew from Hawaii to Kwajalein Atoll in less than 30 min. in November 2011, and in May of this year, under a U.S.-Australian cooperative program, the HIFire 2 scramjet was launched successfully from Hawaii ...